[openstack-dev] [Neutron][os-vif] Expanding vif capability for wiring trunk ports

Matt Riedemann mriedem at linux.vnet.ibm.com
Thu Jun 16 01:33:27 UTC 2016

On 6/13/2016 3:35 AM, Daniel P. Berrange wrote:
> On Thu, Jun 09, 2016 at 05:31:13PM -0600, Carl Baldwin wrote:
>> Hi,
>> You may or may not be aware of the vlan-aware-vms effort [1] in
>> Neutron.  If not, there is a spec and a fair number of patches in
>> progress for this.  Essentially, the goal is to allow a VM to connect
>> to multiple Neutron networks by tagging traffic on a single port with
>> VLAN tags.
>> This effort will have some effect on vif plugging because the datapath
>> will include some changes that will effect how vif plugging is done
>> today.
>> The design proposal for trunk ports with OVS adds a new bridge for
>> each trunk port.  This bridge will demux the traffic and then connect
>> to br-int with patch ports for each of the networks.  Rawlin Peters
>> has some ideas for expanding the vif capability to include this
>> wiring.
>> There is also a proposal for connecting to linux bridges by using
>> kernel vlan interfaces.
>> This effort is pretty important to Neutron in the Newton timeframe.  I
>> wanted to send this out to start rounding up the reviewers and other
>> participants we need to see how we can start putting together a plan
>> for nova integration of this feature (via os-vif?).
> I've not taken a look at the proposal, but on the timing side of things
> it is really way to late to start this email thread asking for design
> input from os-vif or nova. We're way past the spec proposal deadline
> for Nova in the Newton cycle, so nothing is going to happen until the
> Ocata cycle no matter what Neutron want  in Newton. For os-vif our
> focus right now is exclusively on getting existing functionality ported
> over, and integrated into Nova in Newton. So again we're not really looking
> to spend time on further os-vif design work right now.
> In the Ocata cycle we'll be looking to integrate os-vif into Neutron to
> let it directly serialize VIF objects and send them over to Nova, instead
> of using the ad-hoc port-binding dicts.  From the Nova side, we're not
> likely to want to support any new functionality that affects port-binding
> data until after Neutron is converted to os-vif. So Ocata at the earliest,
> but probably more like Pxxxx, unless the Neutron conversion to os-vif gets
> completed unexpectedly quickly.
> Regards,
> Daniel

+1. Nova is past non-priority spec approval freeze for Newton. With 
respect to os-vif it's a priority to integrate that into Nova in Newton [1].

We're also working on refactoring how we allocate and bind ports when 
creating a server [2]. This is a dependency for the routed networks work 
and it's also going to bump up against the changes I'm making in nova 
for get-me-a-network in Newton (which is another priority).

So if vlan-aware-vms changes how nova allocates/binds ports, that's 
going to be dependent on this also, and will have to be worked into the 
Ocata release from Nova's POV.




Matt Riedemann

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